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            <h2 class="title" style="clear: both"><a id="upgrade_4_2_lockng"></a>DB_LOCK_NOTGRANTED</h2>
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      <p>
    In previous releases, configuring lock or transaction timeout values or calling the <a href="../api_reference/C/txnbegin.html" class="olink">DB_ENV-&gt;txn_begin()</a>
    method with the <a href="../api_reference/C/txnbegin.html#txnbegin_DB_TXN_NOWAIT" class="olink">DB_TXN_NOWAIT</a> flag caused database operation methods to return 
    <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a>, or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
    exception.  This required applications to unnecessarily handle multiple errors or 
    exception types.
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    In the Berkeley DB 4.2 release, with one exception, database operations will no longer return
    <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a> or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
    exception.  Instead, database operations will return 
    <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_DEADLOCK" class="olink">DB_LOCK_DEADLOCK</a> or throw a <a href="../api_reference/CXX/dbdeadlock.html" class="olink">DbDeadlockException</a>
    exception.  This change should require no application changes, as applications must 
    already be dealing with the possible <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_DEADLOCK" class="olink">DB_LOCK_DEADLOCK</a> error return or <a href="../api_reference/CXX/dbdeadlock.html" class="olink">DbDeadlockException</a>
    exception from database operations.
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    The one exception to this rule is the <a href="../api_reference/C/dbget.html" class="olink">DB-&gt;get()</a> method using the <a href="../api_reference/C/dbget.html#dbget_DB_CONSUME_WAIT" class="olink">DB_CONSUME_WAIT</a> flag to consume records
    from a Queue.  If lock or transaction timeouts are set, this method and flag combination may
    return <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a> or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
    exception.
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    Applications wanting to distinguish between true deadlocks and timeouts can configure database
    operation methods to return <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a> or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
    exception using the <a href="../api_reference/C/envset_flags.html#envset_flags_DB_TIME_NOTGRANTED" class="olink">DB_TIME_NOTGRANTED</a> flag.
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    The <a href="../api_reference/C/lockget.html" class="olink">DB_ENV-&gt;lock_get()</a> and <a href="../api_reference/C/lockvec.html" class="olink">DB_ENV-&gt;lock_vec()</a> methods will continue to return 
    <a href="../programmer_reference/program_errorret.html#program_errorret.DB_LOCK_NOTGRANTED" class="olink">DB_LOCK_NOTGRANTED</a>, or throw a <a href="../api_reference/CXX/dblocknotgranted.html" class="olink">DbLockNotGrantedException</a>
    exception as they have previously done.
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